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穆松宁, 周广庆. 冬季欧亚大陆北部新增雪盖面积变化与中国夏季气候异常的关系[J]. 大气科学, 2010, 34(1): 213-226. DOI: 10.3878/j.issn.1006-9895.2010.01.20
引用本文: 穆松宁, 周广庆. 冬季欧亚大陆北部新增雪盖面积变化与中国夏季气候异常的关系[J]. 大气科学, 2010, 34(1): 213-226. DOI: 10.3878/j.issn.1006-9895.2010.01.20
MU Songning, ZHOU Guangqing. Relationship between Winter Northern Eurasian Fresh Snow Extent and Summer Climate Anomalies in China[J]. Chinese Journal of Atmospheric Sciences, 2010, 34(1): 213-226. DOI: 10.3878/j.issn.1006-9895.2010.01.20
Citation: MU Songning, ZHOU Guangqing. Relationship between Winter Northern Eurasian Fresh Snow Extent and Summer Climate Anomalies in China[J]. Chinese Journal of Atmospheric Sciences, 2010, 34(1): 213-226. DOI: 10.3878/j.issn.1006-9895.2010.01.20

冬季欧亚大陆北部新增雪盖面积变化与中国夏季气候异常的关系

Relationship between Winter Northern Eurasian Fresh Snow Extent and Summer Climate Anomalies in China

  • 摘要: 利用美国冰雪资料中心 (The National Snow and Ice Data Center) 提供的近40年逐周的卫星反演雪盖资料, 考察了冬季欧亚大陆北部新增雪盖面积 (Total Fresh Snow Extent, 冬季TFSE) 与我国夏季 (6~8月) 气候异常的关系。分析发现, 冬季TFSE与我国夏季气候异常存在明显关联: 当冬季TFSE偏大时, 夏季贝加尔湖以东易盛行异常冷低压, 内蒙古东部和东北西部易出现凉夏, 同时, 东亚副热带西风急流增强, 西太平洋副热带高压易加强且西伸和北扩, 江南地区在副高的控制下易干热; 冬季TFSE偏小时的情况相反。这种显著关联独立于ENSO事件, 并且在近40年来较为稳定; 冬季TFSE与我国江南夏季降水在20世纪90年代初均发生过一次十年际尺度变化, 表现为在20世纪90年代初之后, 冬季TFSE (江南降水) 明显减小 (增多), 同时, 冬季TFSE与江淮夏季降水的正相关关系明显增强。进一步的分析表明, 冬季TFSE可能通过某种途径来影响东亚副热带急流的变化, 进而影响我国夏季气候异常。

     

    Abstract: Utilizing Version 3 NSIDC weekly snow cover data for the period of 1966-2005, the relationships between the increased snow cover in winter over Northern Eurasia (TFSE, Total Fresh Snow Extent) and the climate anomalies in summer (June-August) over China are investigated, which show not only the remarkable negative (positive) correlations with precipitation (temperature) in the south of the Yangtze River (SYR), but also the opposite correlations in the northeast of China. The detailed analysis reveals that: following heavy winter TFSE, there are statistically in summer an intensified anomalous low almost in the entire troposphere in the east of Baikal, an enhanced westerly jet in East Asia (EAWJ), and a strengthened subtropical high in the western Pacific (WPSH) which expands westward and northward to the SYR overhead, as well as weakened convection and vapor flux in the SYR. Under these situations, the SYR region tends to be droughty and hot, and the northeast of China tends to be cold, vice versa. The analysis also shows that the correlations between winter TFSE and summer climate anomalies in China are almost independent of ENSO and stable relatively in recent 40 years. But both the winter TFSE and rainfall in the SYR exhibit a remarkable decadal climate shift at the beginning of the 1990s, in which the winter TFSE (summer SYR rainfall) decreases (increases) obviously later than the early 1990s, and simultaneously, the correlation between winter TFSE and summer rainfall in the Huaihe River valley, just north of the Yangtze River, in China is also enhanced. Further analysis explains that winter TFSE could lead to the summer climate anomalies in China by affecting EAWJ.

     

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